We are at our wits end with this problem, It started with a revolting smell that comes and goes and it led to us finding that we have both black mould and water under bits of our floors. We have had every test and know that it's not tap water or foul water and that there are no dead rodents under there. We've had all our drains tested and none of them is leaking and there are no leaks from household pipes. My husband has taken up various areas of the floor and found different levels of water raging from bone dry through to damp and then to maybe 20ml of water. He has piped out around 100 gallons so far but the smell persists.
Our fllors are floorboard with a void and then concrete. He found some trenches under the floor and has filled those in with concrete to try to level off the floor. we have also installed more air bricks and also taken out odd bricks from the sub floor walls to allow air and water to flow. But the smell persists. Could anyone advise? The house was built in 1970. Thanks Lynne